The present invention is for a new agricultural implement having two folding sections which are pivotally connected to a horizontal central support carrier section. The folding sections are movable from an unfolded, working position that extends the folding sections laterally outwardly and parallel to the horizontal central support carrier section. The folding sections can be swung to a folded position that reduces the width of the grain drill for easy transport.
Agricultural implements that are foldable are widely used and known in the prior art. The prior art agricultural implements have tool bars that do not rotate to collectively adjust the planting depth for the openers. Instead, the planting depth must be adjusted individually for each opener. Further, the prior art implements that have openers often use two disc blades of the same diameter which are sometimes mounted with one blade ahead of the other so that the front blade cuts the trash and the back blade opens the side of the furrow in the ground. This style of mounting the blades of the openers causes problems. One problem is that since the blades are mounted on different centers, as they rotate the rear blade will wear the edge of the front blade. This prevents good soil to seed contact because of a resulting defective groove. In these situations, the seed may merely be compacted into the soil by the implement press wheel without obtaining sufficient side to side soil contact.
The present invention avoids the problem of poor soil to seed contact by mounting different diameter sized blades on a common center. The larger disc blade cuts the trash ahead of the smaller disc blade which opens the furrow. Since the blades have a common center, there is no tendency to wear an edge on the front blade. Further, the groove in the soil cut by these blades is narrower, resulting in a V-shaped groove that provides for better seed to soil contact. This promotes quicker and better seed germination.
Many prior disc openers have not provided an optimal seed furrow or trench for most effective germination. The angle of opening, the width of the resulting groove, and the force required to push the disc opener in the soil and then wedge the blades apart as they rotate to create the seed groove are all affected by the angle of entry into the soil. Prior art openers with bevels directed outwardly have a relatively steep angle of approximately 20.degree. that must be wedged into the soil. As the opposing angle blades rotate, they are forced to slide away from each other, creating a wide groove. This sliding action in conjunction with the outside disc blade bevel causes the discs to be forced upwardly. This results in greater compaction in the seed furrow and requires a greater opposing force to maintain the opener at the desired furrow depth.
The prior art implements in a so-called no-till ground condition are made to be able to apply a significant amount of down pressure per opener to be able to force the opener through the hardened earth. A no-till ground condition is one where the ground surface has not been tilled and the farm operator attempts to control weed and crop growth by applying chemicals, thereby conserving moisture and lessening the amount of wind and water erosion that can take place on the soil. For example, the John Deere 15 foot wide grain drill unit, Model 515, has 22 openers. To be able to apply a high amount of down pressure per opener requires that the unit itself must have this weight on the unit to be able to force the opener into the ground. Currently, the drill units in the industry lift the whole unit in and out of the ground for transport. This means that the seed boxes, the frame and the openers are all lifted together out of the ground. Thus, the prior art implements would have a very high amount of dead weight structure that must be lifted out of the ground. This in turn requires the unit to have heavy structural members and hydraulic cylinders to be able to do this lifting task. This necessitates the use of large tractors with sufficiently large amounts of available high horsepower hydraulic power capability.
The present invention avoids the need to lift the whole frame and seed boxes by having a rotating tool bar that only lifts the openers out of the ground and provides for easy transport. The frame and the seed boxes stay in a static position. Thus, the design and weight of the present invention precludes the need for a heavy structure for lifting the whole frame, seed boxes and openers out of the ground and also very heavy complex and expensive joints for use in the folding and flexing action.
The present invention also includes a rotating tool bar that provides depth adjustment to all the openers simultaneously, although the openers still have individual adjustment mechanisms. The rotating tool bar is connected to a parallel link system that exerts a constant down pressure upon each opener. The rotating tool bar is connected to one or more pressurized cylinders that raise the openers for ground clearance and provide for the depth adjustment for the openers. The present invention uses only one folding pressurized cylinder versus the conventional two cylinders, thereby further reducing the weight and cost of the unit. The rotating tool bar and all of its attached linkage assemblies and tillage tools operate and rotate independently of the implement main frame, thereby significantly reducing the weight lifting requirements of the machine and reducing the need to lift heavy structural members out of soil contact.